U.S. patent application number 10/243768 was filed with the patent office on 2003-11-20 for silicon compound and method for making the same.
Invention is credited to Hashimoto, Yuichi, Mashimo, Seiji, Senoo, Akihiro, Toshida, Yomishi, Ueno, Kazunori.
Application Number | 20030216591 10/243768 |
Document ID | / |
Family ID | 26467163 |
Filed Date | 2003-11-20 |
United States Patent
Application |
20030216591 |
Kind Code |
A1 |
Ueno, Kazunori ; et
al. |
November 20, 2003 |
Silicon compound and method for making the same
Abstract
A silicon compound having a repeating unit represented by the
following general formula (1): 1 wherein R is a hydrogen atom, a
straight or branched alkyl group having 1 to 20 carbon atoms, a
substituted or unsubstituted aryl group, or a substituted or
unsubstituted heterocyclic group, Ar is a substituted or
unsubstituted aryl group or an unsubstituted heterocyclic group, m
is an integer of 2 or more, and n is an integer of 5,000 or
less.
Inventors: |
Ueno, Kazunori; (Ebina-shi,
JP) ; Toshida, Yomishi; (Yokohama-shi, JP) ;
Hashimoto, Yuichi; (Tokyo, JP) ; Senoo, Akihiro;
(Tokyo, JP) ; Mashimo, Seiji; (Tokyo, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
26467163 |
Appl. No.: |
10/243768 |
Filed: |
September 16, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10243768 |
Sep 16, 2002 |
|
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|
09078565 |
May 14, 1998 |
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Current U.S.
Class: |
556/430 ;
313/504; 313/506; 428/448; 428/690; 428/917; 556/413; 556/465;
556/468; 556/479 |
Current CPC
Class: |
C07F 7/0896 20130101;
H01L 51/0052 20130101; Y10T 428/31663 20150401; H01L 51/0053
20130101; H01L 51/0034 20130101; H01L 51/0059 20130101; H01L
51/0062 20130101; H01L 51/007 20130101; H01L 51/0081 20130101; Y10S
428/917 20130101; H01L 51/0094 20130101; C08G 77/60 20130101; H01L
51/005 20130101; H01L 51/5012 20130101; H01L 51/0035 20130101 |
Class at
Publication: |
556/430 ;
556/413; 556/465; 556/468; 556/479; 428/690; 428/917; 428/448;
313/506; 313/504 |
International
Class: |
C07F 007/08; H05B
033/12 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 1997 |
JP |
142956/1997 |
Apr 28, 1998 |
JP |
132635/1998 |
Claims
What is claimed is:
1. A silicon compound having a repeating unit represented by the
following general formula (1): 328wherein R is a hydrogen atom, a
straight or branched alkyl group having 1 to 20 carbon atoms, a
substituted or unsubstituted aryl group, or a substituted or
unsubstituted heterocyclic group, Ar is a substituted or
unsubstituted aryl group or an unsubstituted heterocyclic group, m
is an integer of 2 or more, and n is an integer of 5,000 or
less.
2. A silicon compound according to claim 1, wherein said Ar is a
.pi.-conjugated hydrocarbon group having 12 or more carbon
atoms.
3. A silicon compound according to claim 2, wherein said
.pi.-conjugated hydrocarbon group is a polyphenylene group.
4. A silicon compound according to claim 2, wherein said
.pi.-conjugated hydrocarbon group is a stilbene group.
5. A silicon compound according to claim 1, wherein said Ar is a
fused-ring polycyclic group or a fused-ring poly/heterocyclic
group.
6. A silicon compound according to claim 1, wherein said Ar is a
heterocyclic group.
7. A silicon compound according to claim 6, wherein said
heterocyclic group is a polyheterocyclic group.
8. A silicon compound according to claim 1, wherein said Ar is a
moiety of a tertiary amine.
9. A silicon compound according to claim 8, wherein said moiety of
the tertiary amine is represented by the general formula (4):
329wherein Ar.sub.1 represents a substituted or unsubstituted
arylene group or a substituted or unsubstituted divalent
heterocyclic group, and Ar.sub.2 and Ar.sub.3 each represents a
substituted or unsubstituted aryl group or a substituted or
unsubstituted heterocyclic group.
10. A silicon compound according to claim 9, wherein said Ar.sub.1
is a substituted or unsubstituted arylene group selected from the
group consisting of a phenylene group, a biphenylene group, and a
naphthylene group.
11. A silicon compound according to claim 9, wherein said Ar.sub.1
is a substituted or unsubstituted divalent heterocyclic group
selected from the group consisting of a pyridine group, a furyl
group, and a thiophene group.
12. A silicon compound according to claim 9, wherein said
unsubstituted aryl group of said Ar.sub.2 and Ar.sub.3 is a
polycyclic aryl group.
13. A silicon compound according to claim 9, wherein said
unsubstituted aryl group of said Ar.sub.2 and Ar.sub.3 is a
fused-ring aryl group.
14. A silicon compound according to claim 9, wherein said
unsubstituted heterocyclic group of said Ar.sub.2 and Ar.sub.3 is a
6-member ring or a 5-member ring.
15. A silicon compound according to claim 9, wherein said
unsubstituted heterocyclic group of said Ar.sub.2 and Ar.sub.3 is a
fused-ring heterocyclic group.
16. A silicon compound according to claim 9, wherein said
substituted aryl group or said substituted heterocyclic group has
said substituent selected from the group consisting of halogen,
alkyl, methoxy, alkoxy, aryloxy, amino, nitro, aryl, aralkyl, and
alkenyl.
17. A method for synthesizing of a silicon compound having a
repeating unit represented by the following general formula (1)
comprising reacting a compound represented by the general formula
(2) with a compound represented by the general formula (3):
330wherein R is a hydrogen atom, a straight or branched alkyl group
having 1 to 20 carbon atoms, a substituted or unsubstituted aryl
group, or a substituted or unsubstituted heterocyclic group, Ar is
a substituted or unsubstituted aryl group or an unsubstituted
heterocyclic group, m is an integer of 2 or more, and n is an
integer of 5,000 or less; 331 wherein R is a hydrogen atom, a
straight or branched alkyl group having 1 to 20 carbon atoms, a
substituted or unsubstituted aryl group, or a substituted or
unsubstituted heterocyclic group, and n is an integer of 5,000 or
less; wherein Ar is a substituted or unsubstituted aryl group or an
unsubstituted heterocyclic group, and m is an integer of 2 or
more.
18. A method for synthesizing of a silicon compound according to
claim 17, wherein the reaction is performed in the presence of a
catalyst.
19. A method for synthesizing of a silicon compound according to
claim 18, wherein said catalyst is platinum chloride acid
hydrate.
20. A method for synthesizing of a silicon compound according to
claim 17, wherein said Ar is a .pi.-conjugated hydrocarbon group
having 12 or more carbon atoms.
21. A method for synthesizing of a silicon compound according to
claim 20, wherein said .pi.-conjugated hydrocarbon group is a
polyphenylene group.
22. A method for synthesizing of a silicon compound according to
claim 20, wherein said .pi.-conjugated hydrocarbon group is a
stilbene group.
23. A method for synthesizing of a silicon compound according to
claim 17, wherein said Ar is a fused-ring polycyclic group or a
fused-ring poly/heterocyclic group.
24. A method for synthesizing of a silicon compound according to
claim 17, wherein said Ar is a heterocyclic group.
25. A method for synthesizing of a silicon compound according to
claim 24, wherein said heterocyclic group is a polyheterocyclic
group.
26. A method for synthesizing of a silicon compound according to
claim 17, wherein said Ar is a moiety of a tertiary amine.
27. A method for synthesizing of a silicon compound according to
claim 26, wherein said moiety of the tertiary amine is represented
by the general formula (4): 332wherein Ar.sub.1 represents a
substituted or unsubstituted arylene group or a substituted or
unsubstituted divalent heterocyclic group, and Ar.sub.2 and
Ar.sub.3 each represents a substituted or unsubstituted aryl group
or a substituted or unsubstituted heterocyclic group.
28. A method for synthesizing of a silicon compound according to
claim 26, wherein said Ar.sub.1 is a substituted or unsubstituted
arylene group selected from the group consisting of a phenylene
group, a biphenylene group, and a naphthylene group.
29. A method for synthesizing of a silicon compound according to
claim 26, wherein said Ar.sub.1 is a substituted or unsubstituted
divalent heterocyclic group selected from the group consisting of a
pyridine group, a furyl group, and a thiophene group.
30. A method for synthesizing of a silicon compound according to
claim 26, wherein said unsubstituted aryl group of said Ar.sub.2
and Ar.sub.3 is a polycyclic aryl group.
31. A method for synthesizing of a silicon compound according to
claim 26, wherein said unsubstituted aryl group of said Ar.sub.2
and Ar.sub.3 is a fused-ring aryl group.
32. A method for synthesizing of a silicon compound according to
claim 26, wherein said unsubstituted heterocyclic group of said
Ar.sub.2 and Ar.sub.3 is a 6-member ring or a 5-member ring.
33. A method for synthesizing of a silicon compound according to
claim 26, wherein said unsubstituted heterocyclic group of said
Ar.sub.2 and Ar.sub.3 is a fused-ring heterocyclic group.
34. A method for synthesizing of a silicon compound according to
claim 26, wherein said substituted aryl group or said substituted
heterocyclic group has said substituent selected from the group
consisting of halogen, alkyl, methoxy, alkoxy, aryloxy, amino,
nitro, aryl, aralkyl, and alkenyl.
35. An electroluminescent device comprising a pair of electrodes
and an organic compound layer interposed between said electrodes,
said organic compound layer comprising a silicon compound having a
repeating unit represented by the following general formula (1):
333wherein R is a hydrogen atom, a straight or branched alkyl group
having 1 to 20 carbon atoms, a substituted or unsubstituted aryl
group, or a substituted or unsubstituted heterocyclic group, Ar is
a substituted or unsubstituted aryl group or an unsubstituted
heterocyclic group, m is an integer of 2 or more, and n is an
integer of 5,000 or less.
36. An electroluminescent device according to claim 35, wherein
said Ar is a .pi.-conjugated hydrocarbon group having 12 or more
carbon atoms.
37. An electroluminescent device according to claim 36, wherein
said .pi.-conjugated hydrocarbon group is a polyphenylene
group.
38. An electroluminescent device according to claim 36, wherein
said .pi.-conjugated hydrocarbon group is a stilbene group.
39. An electroluminescent device according to claim 35, wherein
said Ar is a fused-ring polycyclic group or a fused-ring
poly/heterocyclic group.
40. An electroluminescent device according to claim 35, wherein
said Ar is a heterocyclic group.
41. An electroluminescent device according to claim 40, wherein
said heterocyclic group is a polyheterocyclic group.
42. An electroluminescent device according to claim 35, wherein
said Ar is a moiety of a tertiary amine.
43. An electroluminescent device according to claim 42, wherein
said moiety of the tertiary amine is represented by the general
formula (4): 334wherein Ar.sub.1 represents a substituted or
unsubstituted arylene group or a substituted or unsubstituted
divalent heterocyclic group, and Ar.sub.2 and Ar.sub.3 each
represents a substituted or unsubstituted aryl group or a
substituted or unsubstituted heterocyclic group.
44. An electroluminescent device according to claim 35, wherein
said Ar.sub.1 is a substituted or unsubstituted arylene group
selected from the group consisting of a phenylene group, a
biphenylene group, and a naphthylene group.
45. An electroluminescent device according to claim 35, wherein
said Ar.sub.1 is a substituted or unsubstituted divalent
heterocyclic group selected from the group consisting of a pyridine
group, a furyl group, and a thiophene group.
46. An electroluminescent device according to claim 35, wherein
said unsubstituted aryl group of said Ar.sub.2 and Ar.sub.3 is a
polycyclic aryl group.
47. An electroluminescent device according to claim 35, wherein
said unsubstituted aryl group of said Ar.sub.2 and Ar.sub.3 is a
fused-ring aryl group.
48. An electroluminescent device according to claim 35, wherein
said unsubstituted heterocyclic group of said Ar.sub.2 and Ar.sub.3
is a 6-member ring or a 5-member ring.
49. An electroluminescent device according to claim 35, wherein
said unsubstituted heterocyclic group of said Ar.sub.2 and Ar.sub.3
is a fused-ring heterocyclic group.
50. An electroluminescent device according to claim 35, wherein
said substituted aryl group or said substituted heterocyclic group
has said substituent selected from the group consisting of halogen,
alkyl, methoxy, alkoxy, aryloxy, amino groups, nitro, aryl,
aralkyl, and alkenyl.
51. An electroluminescent device according to claim 35, wherein
said organic compound layer functions as a luminescent layer.
52. An electroluminescent device according to claim 35, wherein
said organic compound layer functions as a charge transport
layer.
53. An electroluminescent device according to claim 52, wherein
said charge transport layer is a hole transport layer.
54. An electroluminescent device according to claim 35, wherein
said electroluminescent device further comprises another layer
provided between said electrodes.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a novel silicon compound, a
method for making the same, and an electroluminescent device using
the same.
[0003] 2. Description of the Related Art
[0004] High performance electronic devices require materials for
effectively transporting only electrons or holes. Hole-transporting
materials which transport only holes at a high efficiency have been
widely used for electrophotographic photosensitive members and are
expected as organic luminescent materials. For example, use of
organic photoconductive (OPC) materials is rapidly spreading as
photosensitive materials in electrophotography and the like. OPC
materials have advantages in safety and productivity and costs
compared to inorganic photosensitive materials, and have been
vigorously used for copying machines and printers.
[0005] The OPC members generally have a multilayered structure of a
charge generation layer (CGL) and a charge transport layer (CTL).
The CTL is formed by coating a dispersion of a low molecule charge
transport material (CTM), e.g. a triarylamine, hydrazone or
dialkylaminobenzene derivative, in a transparent polymeric film,
such as a polycarbonate resin. The concentration of the CTM in the
polymer matrix is limited since the CTM crystal deposits at a high
concentration. On the other hand, hole transferability decreases as
the concentration decreases. Further, the CTL is fragile and has a
low tensile strength. Such low mechanical strength causes scratches
and cracks on the OPC member, resulting in image defects.
[0006] Exemplary polymeric charge transport materials are
polystyrenes having hydrazone groups which are disclosed in
Japanese Patent Laid-Open Nos. 2-272005 and 3-180852. These
materials are formed into a film with great difficulty, and have
unsatisfactory hole transport rates and residual potentials.
[0007] Pope et al., first discovered an electroluminescence (EL) of
an organic material, that is, single-crystal anthracene in 1963 (J.
Chem. Phys., 38, 2042 (1963)). Helfinch and Schneider succeeded
observation of relatively strong EL in an injection EL material
containing a solution electrode system having a high injection
efficiency in 1965 (Phys. Rev. Lett., 14, 229 (1965)). Many studies
of organic luminescent materials containing conjugated organic
hosts and conjugated organic activators having fused benzene rings
have been disclosed in U.S. Pat. Nos. 3,172,862, 3,173,050, and
3,710,167; J. Chem. Phys., 44, 2902 (1966); J. Chem. Phys., 58,
1542 (1973); and Chem. Phys. Lett., 36, 345 (1975). Examples of
disclosed organic hosts include naphthalene, anthracene,
phenanthrene, tetracene, pyrene, benzpyrene, chrysene, picene,
carbazole, fluorene, biphenyl, terphenyl, triphenylene oxide,
dihalobiphenyl, trans-stilbene, and 1,4-diphenylbutadiene. Examples
of disclosed activators include anthracene, tetracene and
pentacene. Since these organic luminescent materials are provided
as single layers having a thickness of more than 1 .mu.m, a high
electric field is required for luminescence. Under such a
circumference, thin film devices formed by a vacuum deposition
process have been proposed (for example, "Thin Solid Films" p. 171
(1982); Polymer, 24, 748 (1983); and J. Appl. Phys., 25, L773
(1986)). Although the thin film devices are effective for reducing
the driving voltage, their luminance is far from a level for
practical use.
[0008] Tang et al. developed an EL device having a high luminance
for a low driving voltage (Appl. Phys. Lett., 51, 913 (1987) and
U.S. Pat. No. 4,356,429). The EL device is fabricated by depositing
two significantly thin layers, that is, a charge transport layer
and a luminescent layer, between the positive electrode and the
negative electrode by a vacuum deposition process. Such layered
organic EL devices are disclosed in, for example, Japanese Patent
Laid-Open Nos. 59-194393, 3-264692, and 3-163188, U.S. Pat. Nos.
4,539,507 and 4,720,432, and Appl. Phys. Lett., 55, 1467
(1989).
[0009] Also, an EL device of a triple-layered structure having
independently a carrier transport function and a luminescent
function was disclosed in Jpn. J. Apply. Phys., 27, L269 and L713
(1988). Since the carrier transportability is improved in such an
EL device, the versatility of possible dyes in the luminescent
layer is considerably increased. Further, the device configuration
suggests feasibility of improved luminescence by effectively
trapping holes and electrons (or excimers) in the central
luminescent layer.
[0010] Monolithic organic EL devices are generally formed by vacuum
deposition processes. EL devices having considerable luminance are
also formed by casting processes (as described in, for example,
Extended Abstracts (The 50th Autumn Meeting (1989), p. 1006 and The
51st Autumn Meeting (1990), p. 1041; The Japan Society of Applied
Physics). Considerably high luminance is also achieved by a
single-layered mixture-type EL device, in which the layer is formed
by immersion-coating a solution containing polyvinyl carbazole as a
hole transport compound, an oxadiazole derivative as a charge
transport compound and coumarin-6 as a luminescent material (as
described in Extended Abstracts (The 38th Spring Meeting (1991), p.
1086; The Japan Society of Applied Physics and Related
Societies).
[0011] As described above, the organic EL devices have been
significantly improved and have suggested feasibility of a wide
variety of applications; however, these EL devices have some
problems for practical use, for example, insufficient luminance, a
change in luminance during use for a long period, and deterioration
by atmospheric gas containing oxygen and humidity. Accordingly, a
novel material not having such disadvantages and an
electroluminescent device have been eagerly awaited.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to provide a
silicon compound having excellent charge transport characteristics
and durability.
[0013] It is another object of the present invention to provide a
silicon compound capable of easily forming a uniform film.
[0014] It is a further object of the present invention to provide
an electroluminescent device emitting light with high luminance and
a high efficiency and having high durability.
[0015] It is a still further object of the present invention to
provide an electroluminescent device emitting light with a wide
variety of wavelengths and hues.
[0016] It is another object of the present invention to provide an
electroluminescent device easily produced at relatively low
production costs and having a high degree of safety.
[0017] An aspect of the present invention is a silicon compound
having a repeating unit represented by the following general
formula (1): 2
[0018] wherein R is a hydrogen atom, a straight or branched alkyl
group having 1 to 20 carbon atoms, a substituted or unsubstituted
aryl group, or a substituted or unsubstituted heterocyclic group,
Ar is a substituted or unsubstituted aryl group or an unsubstituted
heterocyclic group, m is an integer of 2 or more, and n is an
integer of 5,000 or less.
[0019] Another aspect of the present invention is a method for
synthesizing of a silicon compound having a repeating unit
represented by the following general formula (1) by reacting a
compound represented by the general formula (2) with a compound
represented by the general formula (3): 3
[0020] wherein R, Ar, m, and n are the same as above; 4
[0021] wherein R is a hydrogen atom, a straight or branched alkyl
group having 1 to 20 carbon atoms, a substituted or unsubstituted
aryl group, or a substituted or unsubstituted heterocyclic group,
and n is an integer of 5,000 or less;
CH.sub.2.dbd.CH--(CH.sub.2).sub.m-2--Ar (3)
[0022] wherein Ar is a substituted or unsubstituted aryl group or
an unsubstituted heterocyclic group, and m is an integer of 2 or
more.
[0023] A further aspect of the present invention is an
electroluminescent device comprising a pair of electrodes and an
organic compound layer interposed between said electrodes, said
organic compound layer comprising a silicon compound having a
repeating unit represented by the following general formula (1):
5
[0024] wherein R is a hydrogen atom, a straight or branched alkyl
group having 1 to 20 carbon atoms, a substituted or unsubstituted
aryl group, or a substituted or unsubstituted heterocyclic group,
Ar is a substituted or unsubstituted aryl group or an unsubstituted
heterocyclic group, m is an integer of 2 or more, and n is an
integer of 5,000 or less.
[0025] The silicon compound in accordance with the present
invention has excellent charge transport characteristics and can
form a uniform and smooth film, hence it is useful as a charge
transport material.
[0026] The method in accordance with the present invention enables
ready production of the silicon compound.
[0027] The electroluminescent device in accordance with the present
invention has high luminance at a low voltage for long periods, and
can emit a variety of hues. For example, the electroluminescent
device can emit primaries, i.e., red, blue and green; hence it can
be used in displays. The device can be produced by a vacuum
deposition or casting process at low production costs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematic view of an embodiment of an
electroluminescent device in accordance with the present
invention;
[0029] FIG. 2 is a schematic view of an embodiment of an
electroluminescent device in accordance with the present
invention;
[0030] FIG. 3 is a schematic view of an embodiment of an
electroluminescent device in accordance with the present
invention;
[0031] FIG. 4 is a schematic view of an embodiment of an
electroluminescent device in accordance with the present invention;
and
[0032] FIG. 5 is an IR spectrum of Compound 19 synthesized in
Example 1 in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0033] The present inventors have studied intensively towards the
resolution of problems caused by the charge transport material in
the electroluminescent device, and have discovered that a silicon
compound having a polysilane main chain and aryl groups has
excellent charge transport characteristics and film formability and
the resulting film has excellent stability. The present invention
is completed under such findings.
[0034] The silicon compound in accordance with the present
invention is represented by the following general formula (1):
6
[0035] In the formula (1), R is a hydrogen atom, a straight or
branched alkyl group having 1 to 20 carbon atoms and preferably 1
to 10, a substituted or unsubstituted aryl group, or a substituted
or unsubstituted heterocyclic group. Examples of the straight or
branched alkyl groups having 1 to 20 carbon atoms include straight
alkyl groups, such as methyl, ethyl, propyl, hexyl and octyl
groups, and branched alkyl groups, such as isopropyl and isobutyl
groups. Examples of unsubstituted aryl groups include polycyclic
aryl groups, such as phenyl, biphenyl and terphenyl groups, and
fused-ring aryl groups, such as naphthyl and anthranyl groups.
Examples of unsubstituted heterocyclic groups include 6- and
5-membered rings, such as pyridyl, furyl, thienyl and pyrrolyl, and
fused-ring heterocyclic groups such as acrydinyl. In the
substituted aryl group and substituted heterocyclic group, each of
the above-mentioned aryl and heterocyclic groups has a substituent
group. Examples of the substituent groups include halogen atoms,
e.g. chlorine and bromine; alkyl groups, e.g. methyl and ethyl
groups; alkoxyl groups, e.g. methoxy and ethoxy groups; aryloxyl
groups, e.g. a phenoxy group; primary and secondary amino groups; a
nitro group; aryl groups, e.g. phenyl and tolyl groups; and aralkyl
groups, e.g. benzyl and phenethyl groups.
[0036] In the formula (1), m is an integer of 2 or more and
preferably 2 to 20, and n is an integer of 5,000 or less and
preferably 30 to 1,000. Although the values of m and n are not
limited to these ranges, these values are preferred in view of
reactivity and yield in the production of the compound.
[0037] In the formula (1), Ar is a substituted or unsubstituted
aryl group or an unsubstituted heterocyclic group. Examples of such
groups are as follows:
[0038] (I) .pi.-Conjugated Hydrocarbons having 12 or more Carbon
Atoms:
[0039] Examples include polyphenyl groups, such as biphenyl,
terphenyl and tetraphenyl, and stilbene groups, such as a naphthyl
stilbene group.
[0040] (II) Fused-Ring Hydrocarbon Groups and Fused-Ring
Heterocyclic Groups:
[0041] Examples of the fused-ring hydrocarbon groups include
naphthyl, anthryl, pyrenyl, and fluorenyl groups. Examples of
fused-ring heterocyclic groups include benzoxazolyl, dibenzofuryl,
carbazolyl, and phenazone groups.
[0042] (III) Aromatic Polycyclic Groups:
[0043] Examples of the aromatic polycyclic groups include pyridyl,
furyl, thienyl and pyrrolyl groups.
[0044] These groups (I) to (III) may have substituent groups.
Examples of the substituent groups include halogen atoms, e.g.
fluorine, chlorine, bromine and iodine; alkyl groups, e.g. methyl,
ethyl, n-propyl and isopropyl; alkoxyl groups, e.g. methoxy, ethoxy
and phenoxy; aralkyl groups, e.g. benzyl, phenethyl and
propylphenyl; a nitro group; cyano groups; substituted amino
groups, e.g. dimethylamino, dibenzylamino, diphenylamino, and
morpholino; aryl groups, e.g. phenyl, tolyl, biphenyl, naphthyl,
anthryl, and pyrenyl; and heterocyclic groups, e.g. pyridyl,
thienyl, furyl, quinolyl, and carbazolyl.
[0045] (IV) Tertiary Amines each having a Substituted or
Unsubstituted Arylene Group or Substituted or Unsubstituted
Divalent Heterocyclic Group:
[0046] These groups are represented by the general formula (4):
7
[0047] In the formula (4), Ar.sub.1 represents a substituted or
unsubstituted arylene group or a substituted or unsubstituted
divalent heterocyclic group. Examples of the substituted or
unsubstituted arylene group include phenylene, biphenylene and
naphthylene groups. Examples of the substituted or unsubstituted
divalent heterocyclic groups include divalent groups of pyridine,
furan, and thiophene.
[0048] In the formula (4), Ar.sub.2 and Ar.sub.3 each represents a
substituted or unsubstituted aryl group or a substituted or
unsubstituted heterocyclic group. Examples of unsubstituted aryl
groups include phenyl; polycyclic aryl groups, e.g. biphenyl and
terphenyl groups; and fused-ring aryl groups, e.g. naphthyl and
anthranyl groups. Examples of unsubstituted heterocyclic groups
include 6- and 5-member heterocyclic groups, e.g. pyridyl, furyl,
thienyl and pyrrolyl groups; and fused-ring heterocyclic groups,
e.g. acrydinyl. In the substituted aryl group and substituted
heterocyclic group, each of the above-mentioned aryl and
heterocyclic groups has a substituent group. Examples of the
substituent groups include halogen atoms, e.g. chlorine and
bromine; alkyl groups, e.g. methyl and ethyl groups; alkoxyl
groups, e.g. methoxy and ethoxy groups; aryloxyl groups, e.g. a
phenoxy group; primary and secondary amino groups; a nitro group;
aryl groups, e.g. phenyl and tolyl groups; aralkyl groups, e.g.
benzyl and phenethyl groups; and alkenyl groups, e.g. formyl,
acetyl and vinyl groups.
[0049] A silicon compound having the repeating unit of formula (1)
is terminated by an appropriate terminal group. In general, the
silicon compound is terminated with the group: 8
[0050] Accordingly, in a preferred embodiment the silicon compound
of formula (1) has the formula: 9
[0051] The silicon compound in accordance with the present
invention represented by the formula (1) is synthesized by the
reaction of a polysilane compound with a compound having any one of
the groups (I) to (III). The reaction is preferably performed in
the presence of a catalyst, such as platinum chloride acid
hydrate.
[0052] The process of synthesis of the silicon compound is now
described. The silicon compound represented by the formula (1) is
synthesized by the reaction of a compound represented by the
formula (2) with a compound represented by the formula (3): 10
[0053] wherein R, Ar, m and n are the same as above; 11
[0054] wherein R and n are the same as above; and
CH.sub.2.dbd.CH--(CH.sub.2).sub.m-2--Ar (3)
[0055] wherein Ar and m are the same as above.
[0056] The molar ratio, the compound of the formula (2) : the
compound of the formula (3), is preferably in a range of 1.0:10 to
10:1.0. It is preferable that the platinum chloride acid hydrate
catalysis be added in an amount of 0.1 to 0.01 mole to 1 mole of
the compound of the formula (2). Preferably, the reaction is
performed in a solvent such as tetrahydrofuran at a temperature of
20 to 66.degree. C. for a time of 3 to 10 hours.
[0057] Examples of the silicon compounds represented by the formula
(1) will be described below without limiting the scope of the
present invention.
1 Compound m R Ar 1 2 --CH.sub.3 12 2 2 --CH.sub.3 13 3 2
--CH.sub.3 14 4 2 --CH.sub.3 15 5 2 --CH.sub.3 16 6 2 --CH.sub.3 17
7 2 --CH.sub.3 18 8 2 --CH.sub.3 19 9 2 --CH.sub.3 20 10 2
--CH.sub.3 21 11 2 --C.sub.2H.sub.5 22 12 2 --C.sub.2H.sub.5 23 13
2 --C.sub.2H.sub.5 24 14 2 -n-C.sub.3H.sub.7 25 15 2 26 27 16 2
--C.sub.6H.sub.13 28 17 2 --C.sub.8H.sub.17 29 18 2
--C.sub.18H.sub.37 30 19 2 31 32 20 2 33 34 21 2 35 36 22 2 37 38
23 2 39 40 24 2 41 42 25 2 43 44 26 2 45 46 27 2 47 48 28 3
--CH.sub.3 49 29 3 --CH.sub.3 50 30 3 --CH.sub.3 51 31 3
--C.sub.2H.sub.5 52 32 3 --C.sub.3H.sub.7 53 33 3 54 55 34 4
--CH.sub.3 56 35 4 --CH.sub.3 57 36 4 --CH.sub.3 58 37 4
--C.sub.3H.sub.7 59 38 4 --C.sub.8H.sub.17 60 39 5 --CH.sub.3 61 40
5 62 63 41 2 --CH.sub.3 64 42 2 --CH.sub.3 65 43 2 --CH.sub.3 66 44
2 --CH.sub.3 67 45 2 --CH.sub.3 68 46 2 --CH.sub.3 69 47 2
--CH.sub.3 70 48 2 --CH.sub.3 71 49 2 --CH.sub.3 72 50 2 --CH.sub.3
73 51 2 --CH.sub.3 74 52 2 --CH.sub.3 75 53 2 --CH.sub.3 76 54 2
--CH.sub.3 77 55 2 --CH.sub.3 78 56 2 --CH.sub.3 79 57 2 --CH.sub.3
80 58 2 --C.sub.2H.sub.5 81 59 2 --C.sub.2H.sub.5 82 60 2
--C.sub.2H.sub.5 83 61 2 --C.sub.2H.sub.5 84 62 2 --C.sub.3H.sub.7
85 63 2 --C.sub.3H.sub.7 86 64 2 --C.sub.3H.sub.7 87 65 2 88 89 66
2 90 91 67 2 92 93 68 2 94 95 69 2 96 97 70 2 98 99 71 3 --CH.sub.3
100 72 3 --CH.sub.3 101 73 3 --C.sub.3H.sub.7 102 74 3
--C.sub.8H.sub.17 103 75 3 104 105 76 4 --C.sub.2H.sub.5 106 77 4
--C.sub.8H.sub.17 107 78 4 108 109 79 5 --CH.sub.3 110 80 5
--C.sub.2H.sub.5 111 81 2 --CH.sub.3 112 82 2 --CH.sub.3 113 83 2
--CH.sub.3 114 84 2 --CH.sub.3 115 85 2 --CH.sub.3 116 86 2
--CH.sub.3 117 87 2 --CH.sub.3 118 88 2 --CH.sub.3 119 89 2
--CH.sub.3 120 90 2 --CH.sub.3 121 91 2 --CH.sub.3 122 92 2
--CH.sub.3 123 93 2 --CH.sub.3 124 94 2 --CH.sub.3 125 95 2
--CH.sub.3 126 96 2 --CH.sub.3 127 97 2 --CH.sub.3 128 98 2
--CH.sub.3 129 99 2 --CH.sub.3 130 100 2 --CH.sub.3 131 101 2
--CH.sub.3 132 102 2 --CH.sub.3 133 103 2 --CH.sub.3 134 104 2
--CH.sub.3 135 105 3 --CH.sub.3 136 106 3 --CH.sub.3 137 107 3
--CH.sub.3 138 108 3 --C.sub.2H.sub.5 139 109 3 --C.sub.8H.sub.17
140 110 3 141 142 111 2 143 144 112 2 145 146 113 2 147 148 114 2
149 150 115 2 151 152 116 2 --C.sub.3H.sub.7 153 117 2
--C.sub.18H.sub.37 154 118 2 --C.sub.8H.sub.17 155 119 3 156 157
120 3 158 159 Compound m R Ar.sub.1 Ar.sub.2 Ar.sub.3 121 2 Ph 160
161 162 122 2 Ph 163 164 165 123 2 Ph 166 167 168 124 2 Ph 169 170
171 125 2 Ph 172 173 174 126 2 Ph 175 176 177 127 2 Ph 178 179 180
128 2 Ph 181 182 183 129 2 Ph 184 185 186 130 2 Ph 187 188 189 131
2 CH.sub.3 190 191 192 132 2 CH.sub.3 193 194 195 133 2 CH.sub.3
196 197 198 134 2 CH.sub.3 199 200 201 135 2 CH.sub.3 202 203 204
136 2 CH.sub.3 205 206 207 137 2 CH.sub.3 208 209 210 138 2
CH.sub.3 211 212 213 139 2 CH.sub.3 214 215 216 140 3 CH.sub.3 217
218 219 141 2 CH.sub.3 220 221 222 142 3 CH.sub.3 223 224 225 143 3
CH.sub.3 226 227 228 144 3 CH.sub.3 229 230 231 145 3 CH.sub.3 232
233 234 146 3 CH.sub.3 235 236 237 147 3 CH.sub.3 238 239 240 148 3
CH.sub.3 241 242 243 149 3 CH.sub.3 244 245 246 150 3 CH.sub.3 247
248 249 151 2 Ph 250 251 252 152 2 Ph 253 254 255 153 2 Ph 256 257
258 154 2 Ph 259 260 261 155 2 Ph 262 263 264 156 2 Ph 265 266 267
157 2 Ph 268 269 270 158 2 CH.sub.3 271 272 273 159 2 CH.sub.3 274
275 276 160 2 CH.sub.3 277 278 279
[0058] The electroluminescent device in accordance with the present
invention comprises a pair of electrodes and an organic layer
composed of the silicon compound represented by the formula (1)
displaced between the electrodes. The silicon compound is formed
between the positive and negative electrodes by a vacuum deposition
or solution coating process. The thickness of the organic layer is
preferably 2 .mu.m or less, more preferably 0.5 .mu.m or less, and
most preferably 0.05 .mu.m to 0.5 .mu.m.
[0059] In the electroluminescent device in accordance with the
present invention, a plurality of layers may be provided between
the two electrodes. In this case, at least one layer among these
layers is composed of the compound represented by the formula (1).
The luminescent color of the electroluminescent device can be
determined by selecting the compound represented by the formula
(1).
[0060] The electroluminescent device in accordance with the present
invention will now be described in detail with reference to the
drawings.
[0061] FIG. 1 is a schematic cross-sectional view of an embodiment
of the electroluminescent device in accordance with the present
invention. A positive electrode 2, a luminescent layer 3 and a
negative electrode 4 are formed on a substrate 1 in that order. The
luminescent layer 3 may be composed of a single compound having
hole transportability, electron transportability and luminescence,
or a mixture of compounds each having one of these properties.
[0062] FIG. 2 is a schematic cross-sectional view of another
embodiment of the electroluminescent device in accordance with the
present invention. A positive electrode 2, a hole transport layer
5, an electron transport layer 6 and a negative electrode 4 are
formed on a substrate 1 in that order. The hole transport layer 5
and the electron transport layer 6 form a luminescent layer 3. The
hole transport layer 5 may be composed of a luminescent material
having hole transportability or a mixture including such a material
and a non-luminescent material having hole transportability. The
luminescent and non-luminescent materials may also have electron
transportability. The electron transport layer 6 may be composed of
a luminescent material having electron transportability or a
mixture including such a material and a non-luminescent material
having electron transportability. The luminescent and
non-luminescent materials may also have hole transportability.
[0063] FIG. 3 is a schematic cross-sectional view of a further
embodiment of the electroluminescent device in accordance with the
present invention. A positive electrode 2, a hole transport layer
5, a luminescent layer 3, an electron transport layer 6 and a
negative electrode 4 are formed on a substrate 1 in that order. In
this configuration, carrier transport and luminescence are
performed in the individual layers. Such a configuration permits a
wide variety of combinations of a material having excellent hole
transportability, a material having excellent electron
transportability and a material having excellent luminescence.
Further, the configuration permits the use of various compounds
emitting light with different wavelengths; hence the hue of the
luminescent light can be controlled within a wide range. Trapping
effectively holes and electrons (or excimers) in the central
luminescent layer will increase the luminescent efficiency.
[0064] FIG. 4 is a schematic cross-sectional view of a still
further embodiment of the electroluminescent device in accordance
with the present invention. A positive electrode 2, a hole
injection/transport layer 7, a hole transport layer 5, an electron
transport layer 6 and a negative electrode 4 are formed on a
substrate 1 in that order.
[0065] The silicon compound in accordance with the present
invention represented by the formula (1) has excellent luminescence
compared to known compounds, and can be used for the
electroluminescent devices shown in FIGS. 1 to 4.
[0066] The silicon compound represented by the formula (1) has hole
transportability and/or carrier transportability depending on the
types of the substituent groups. A silicon compound or a
combination of different silicon compounds may be used in the
configurations shown in FIGS. 1 to 4. In the present invention,
another layer or other layers can be provided in addition to at
least one silicon compound layer.
[0067] The silicon compound represented by the formula (1) is used
as a constituent in the luminescent layer or a charge transport
layer. These layers may further include various compounds used in
electrophotographic photosensitive members. Examples of the
compounds include hole transport materials, luminescent hole
transport materials (for example, compounds shown in Tables 1 to
5), electron transport materials, and luminescent electron
transport materials (for example, compounds shown in Tables 6 to
9).
[0068] Table 10 illustrates examples of dopant dyes. The addition
of a trace amount of dopant dye in the luminescent layer will
significantly increase the luminescent efficiency or will change
the luminescent color.
2TABLE 1 Hole Transport Compound 280 281 282 283 284 285
[0069]
3TABLE 2 Hole Transport Compound 286 287 288 289 290
[0070]
4TABLE 3 Hole Transport Compound 291
[0071]
5TABLE 4 Hole Transport Compound 292 293 294 295 296 297 298
[0072]
6TABLE 5 Hole Transport Compound 299 300
[0073]
7TABLE 6 Electron Transport Compound 301 M: Al, Ga 302 M: Zn, Mg,
Be 303 M: Zn, Mg, Be 304 M: Zn, Mg, Be
[0074]
8TABLE 7 Electron Transport Compound 305 306 307 308
[0075]
9TABLE 8 Electron Transport Compound 309 310 311 312
[0076]
10TABLE 9 Electron Transport Compound 313 314 315 316 317 318
[0077]
11TABLE 10 Dopant Dye 319 320 321 322 323 324 325
[0078] In the electroluminescent device in accordance with the
present invention, each layer on the substrate is formed by a
vacuum deposition process or a coating process using a combination
of the relevant compound and a suitable binding resin.
[0079] Non-limiting examples of the binding resins include
polyvinyl carbazole resins, polycarbonate resins, polyester resins,
polyarylate resins, butyral resins, polystyrene resins, polyvinyl
acetal resins, diallyl phthalate resins, acrylate resins,
methacrylate resins, phenol resins, epoxy resins, silicon resins,
polysulfone resins, and urea resins.
[0080] These binding resins can be used alone or in
combination.
[0081] Materials for the positive electrode have preferably large
work functions. Examples of preferred materials include nickel,
gold, platinum, palladium, selenium, rhenium, and iridium, alloys
thereof, tin oxide, indium tin oxide (ITO), and copper iodide.
Also, conductive polymers, such as poly(3-methylthiophene),
polyphenylene sulfide and polypyrrole, can be used.
[0082] Preferred materials for the negative electrode have small
work functions. Examples of such materials include silver, lead,
tin, magnesium, aluminum, calcium, manganese, indium and chromium,
and alloys thereof.
[0083] It is preferable that at least one of the materials for the
positive and negative electrodes has a transmittance of at least
50% at the wavelength range of the light emerging from the
electroluminescent device.
[0084] Examples of transparent substrates used in the present
invention include glass plates and plastic films.
[0085] Since the silicon compound in accordance with the present
invention represented by the formula (1) has excellent hole
transportability and can form a uniform and smooth film, it is
suitable for a hole transport material in an organic EL device.
EXAMPLES
[0086] The present invention is described in further detail with
reference to the following examples.
Example 1
Synthesis of Compound 2
[0087] Five grams of polymethylsilane was dissolved into 50 ml of
dried tetrahydrofuran (THF), 0.05 g of platinum chloride acid
hydrate and 0.5 g of 4-vinylterphenyl were added, and the THF
solution was stirred at room temperature (25.degree. C.) for 10
hours. After the THF solution was concentrated by evacuation, it
was placed into 100 ml of methanol. A white precipitate (5.1 g;
yield: 92.7%) was obtained. The product (Compound 2) had a weight
average molecular weight of 7,000 according to a styrene
calibration curve after gel permeation chromatography (GPC).
Example 2
Synthesis of Compound 139
[0088] Five grams of polymethylsilane was dissolved into 50 ml of
dried THF, 0.05 g of platinum chloride acid-hydrate and 0.5 g of
N,N-(p-ditolylamino)styrene were added, and the THF solution was
stirred at room temperature (25.degree. C.) for 10 hours. After the
THF solution was concentrated by evacuation, it was placed into 100
ml of methanol. A white precipitate (4.8 g; yield: 87%) was
obtained. The product had a weight average molecular weight of
3,500 according to the styrene calibration curve after gel
permeation chromatography (GPC). FIG. 5 is an infrared spectrum of
the resulting Compound 139.
Example 3
Synthesis of Compound 145
[0089] Five grams of polymethylsilane was dissolved into 50 ml of
dried THF, 0.05 g of platinum chloride acid hydrate and 0.5 g of
N,N-p-ditolyl(p-allylphenyl)amine were added, and the THF solution
was stirred at room temperature (25.degree. C.) for 10 hours. After
the THF solution was concentrated by evacuation, it was placed into
100 ml of methanol. A white precipitate (4.8 g; yield: 78%) was
obtained. The product (Compound 145) had a weight average molecular
weight of 3,000 according to the styrene calibration curve after
gel permeation chromatography (GPC).
Example 4
Measurement of Hole Mobility
[0090] Of each of the polysilane compounds (Compounds 139 and 145)
of Examples 2 and 3, 2.5 g was dissolved into 10 ml of toluene. The
solution was applied by a Meyer bar onto an aluminum substrate
provided with a titanium oxyphthalocyanine layer with a thickness
of 1,000 .ANG., which was deposited by a vacuum deposition process,
to form a coating layer having a thickness of 15 .mu.m. The hole
mobility in the sample was determined by a xerographic
time-of-flight method. The results are as follows:
.mu.d=3.5.times.10.sup.-4 cm.sup.2/V.multidot.sec Compound 139:
.mu.d=2.3.times.10.sup.-4 cm.sup.2/V.multidot.sec Compound 145:
[0091] Both coating layers were satisfactorily formed and did not
have any cracks.
Comparative Example 1
[0092] A film was formed as in Example 4, but the following
compound was used instead of Compound 139 or 145. 326
[0093] The hole mobility of the sample is as follows:
.mu.d=3.5.times.10.sup.-4 cm.sup.2/V19 sec
[0094] The coating layer had some cracks and a rough surface.
Example 5
[0095] An indium tin oxide (ITO) layer with a thickness of 100 nm
was deposited on a glass plate by a sputtering process, and the
resulting transparent substrate was cleaned with deionized water
and isopropyl alcohol. Next, 0.20 g of Compound 8 was dissolved
into 10 ml of THF to prepare a coating solution, and then the
coating solution was applied onto the transparent substrate by a
spin coating process to form a coating layer with a thickness of
110 nm. An aluminum electrode with a thickness of 200 nm was
deposited by a vacuum deposition process to form a device having
the configuration shown in FIG. 1.
[0096] A direct current of 10 V was applied between the ITO
positive electrode and the Al negative electrode. A current flow of
12 mA/cm.sup.2 and a blue luminescence with a luminance of 200
cd/m.sup.2 were observed.
Comparative Example 2
[0097] A transparent glass substrate provided with an ITO layer
having a thickness of 100 nm deposited by a sputtering process was
cleaned with deionized water and isopropyl alcohol. Next, 0.20 g of
methylphenylpolysilane (weight average molecular weight: 30,000)
was dissolved into 10 ml of THF to prepare a coating solution. The
coating solution was applied onto the transparent substrate by a
dip coating process to form a coating layer with a thickness of 110
nm. An aluminum electrode with a thickness of 200 nm was deposited
thereon by a vacuum deposition process to form a device having the
configuration shown in FIG. 1.
[0098] A direct current of 12 V was applied between the ITO
positive electrode and the Al negative electrode. A current flow of
0.150 mA/cm.sup.2 and no luminescence were observed.
Example 6
[0099] A transparent glass substrate provided with an ITO layer
having a thickness of 100 nm deposited by a sputtering process was
cleaned with deionized water and isopropyl alcohol. Next, 0.50 g of
Compound 61 was dissolved into 25 ml of THF to prepare a coating
solution. The coating solution was applied onto the transparent
substrate by a dip coating process to form a coating layer with a
thickness of 60 nm as a hole transport layer. An aluminum
quinolinol layer with a thickness of 50 nm as an electron transport
layer was deposited thereon by a vacuum deposition process. A
metallic electrode having a composition of Mg:Ag=10:1 by atomic
ratio was deposited thereon by a vacuum deposition process to form
a device having the configuration shown in FIG. 2.
[0100] A direct current of 7 V was applied between the ITO positive
electrode and the Mg/Ag negative electrode. A current flow of 11
mA/cm.sup.2 and a green luminescence having a luminance of 265
cd/m.sup.2 were observed. A voltage with a current density of 10
mA/cm.sup.2 was applied to the sample for 2,000 hours. The
luminance was 250 cd/m.sup.2 at the start and changed to 225
cd/m.sup.2 at the end.
Example 7
[0101] A transparent glass substrate provided with an ITO layer
having a thickness of 100 nm deposited by a sputtering process was
cleaned with deionized water and isopropyl alcohol. Next, 0.20 g of
vinylcarbazole was dissolved into 15 ml of THF to prepare a coating
solution. The coating solution was applied onto the transparent
substrate by a spin coating process to form a coating layer with a
thickness of 40 nm as a hole transport layer. A coating solution
containing 0.20 g of Compound 100 in 20 ml of THF was applied
thereon by a spin coating process to form a luminescent layer with
a thickness of 15 nm. An aluminum quinolinol layer with a thickness
of 50 nm as an electron transport layer was deposited thereon by a
vacuum deposition process. A metallic electrode having a
composition of Al:Li=97:3 by atomic ratio was deposited thereon by
a vacuum deposition process to form a device having the
configuration shown in FIG. 3.
[0102] A direct current of 12 V was applied between the ITO
positive electrode and the Al/Li negative electrode. A current flow
of 25 mA/cm.sup.2 and a green luminescence having a luminance of
330 cd/m.sup.2 were observed. A voltage with a current density of
15 mA/cm.sup.2 was applied to the sample for 2,000 hours. The
luminance was 250 cd/m.sup.2 at the start and changed to 213
cd/m.sup.2 at the end.
Example 8
[0103] A transparent glass substrate provided with an ITO layer
having a thickness of 100 nm deposited by a sputtering process was
cleaned with deionized water and isopropyl alcohol. Next, 0.20 g of
Compound 88 was dissolved into 15 ml of THF to prepare a coating
solution. The coating solution was applied onto the transparent
substrate by a spin coating process to form a coating layer with a
thickness of 30 nm as a hole injection/transport layer. A hole
transport layer with a thickness of 20 nm composed of .alpha.-NPD
(N,N'-Diphenyl-N,N'-di(naphthyl)-4,4'-diamino-- biphenyl)
represented by the formula (5) and an electron transport layer with
a thickness of 50 nm composed of an aluminum quinolinol layer were
deposited thereon by a vacuum deposition process in that order. An
aluminum electrode was deposited thereon by a vacuum deposition
process to form a device having the configuration shown in FIG. 4.
327
[0104] A direct current of 10 V was applied between the ITO
positive electrode and the Al negative electrode. A current flow of
21 mA/ cm.sup.2 and a green luminescence having a luminance of 425
cd/m.sup.2 were observed. A voltage with a current density of 11
mA/cm.sup.2 was applied to the sample for 2,000 hours. The
luminance was 250 cd/m.sup.2 at the start and changed to 230
cd/m.sup.2 at the end.
Example 9
[0105] A transparent glass substrate provided with an ITO layer
having a thickness of 100 nm deposited by a sputtering process was
cleaned with deionized water and isopropyl alcohol. Next, 0.50 g of
Compound 139 was dissolved into 25 ml of THF to prepare a coating
solution. The coating solution was applied onto the transparent
substrate by a dip coating process to form a coating layer with a
thickness of 60 nm as a hole transport layer. An aluminum
quinolinol layer with a thickness of 50 nm as an electron transport
layer was deposited thereon by a vacuum deposition process. A
metallic electrode having a composition of Mg:Ag=10:1 by atomic
ratio was deposited thereon by a vacuum deposition process to form
a device having the configuration shown in FIG. 2.
[0106] A direct current of 8 V was applied between the ITO positive
electrode and the Mg/Ag negative electrode. A current flow of 13
mA/cm.sup.2 and a green luminescence having a luminance of 470
cd/m.sup.2 were observed. A voltage with a current density of 5
mA/cm.sup.2 was applied to the sample for 2,000 hours. The
luminance was 250 cd/m.sup.2 at the start and changed to 220
cd/m.sup.2 at the end.
Example 10
[0107] An ITO layer with a thickness of 100 nm was deposited on a
glass plate by a sputtering process, and the resulting transparent
substrate was cleaned with deionized water and isopropyl alcohol.
Next, 0.20 g of Compound 104 was dissolved into 10 ml of THF to
prepare a coating solution, and then the coating solution was
applied onto the transparent substrate by a spin coating process to
form a coating layer with a thickness of 100 nm. An aluminum
electrode with a thickness of 200 nm was deposited thereon by a
vacuum deposition process to form a device having the configuration
shown in FIG. 1.
[0108] A direct current of 12 V was applied between the ITO
positive electrode and the Al negative electrode. A current flow of
15 mA/cm.sup.2 and a red luminescence with a luminance of 210
cd/m.sup.2 were observed.
[0109] While the present invention has been described with
reference to what are presently considered that the invention is
not limited to the disclosed embodiments. To the contrary, the
invention is intended to cover various modifications and equivalent
arrangements, included within the spirit and scope of the appended
claims. The scope of the following claims is to be accorded the
broadest interpretation so as to encompass all such modifications
and equivalent structures and functions.
* * * * *